1. Field of the Invention
This invention relates to a process for producing a photographic light-sensitive material. More particularly, it is concerned with a process for producing a photographic light-sensitive material which comprises providing a light-sensitive photographic emulsion layer and/or a gelatin back layer directly on both sides of a support having a surface resistivity of more than 10.sup.14 .OMEGA. without incorporating any antistatic agent in the support, without providing any antistatic layer on the support, and without forming static marks.
2. Description of the Prior Art
Photographic light-sensitive materials (hereinafter referred to merely as light-sensitive materials) are generally produced by coating light-sensitive photographic emulsions (hereinafter referred to merely as photographic emulsions) containing various additives on a support and subjecting the support so coated to cooling and drying procedures.
In these light-sensitive materials, the coating of photographic emulsions is usually applied to both sides of the support. For example, a light-sensitive emulsion is coated on both sides of a support, or a light-sensitive emulsion is coated on one side of a support and on the other side a non-sensitive photographic layer is provided to prevent curling, halation and so on. In accordance with the procedure usually employed for production of these both sides-coated materials, a desired photographic emulsion layer is first provided on one side of a support, which is then cooled and dried; the resulting member is wound around a reel; and thereafter, while transporting the member, another photographic emulsion layer is provided on the opposite side of the support, which is then cooled and dried.
In this procedure, however, wherein the photographic emulsion layers are provided on both sides of the support by coating the photographic emulsions firstly on one side of the support and then on the other side, the support is inevitably delivered and conveyed with one surface thereof exposed. Therefore, when the support has a surface resistivity of greater than 10.sup.14 .OMEGA., electrostatic discharge occurs when the exposed surface of the support comes in contact with a conveyor roll. This leads to fogging of the photographic emulsion layer provided on the reverse side and to the formation of static marks.
"Static marks" are those dot or branch-like marks which appear on a light-sensitive material on subjecting it to development processing. The formation of static marks is believed to be from the discharge of electric charges accumulated by contact, friction and so on of the light-sensitive materials with each other or with other materials, leading to fogging of the photographic emulsion layer.
Therefore, when the surface resistivity of the support is greater than 10.sup.14 .OMEGA., it has been necessary to incorporate an antistatic agent in the support or to coat the antistatic agent on the support (a so-called subbing layer.)
Heretofore, a subbing layer has usually been provided on a support in order to firmly bond the hydrophobic plastic support and the hydrophilic photographic emulsion layer. However, incorporation of an antistatic agent into the subbing layer leads to a reduction in adhesive strength. Moreover, upon coating of the subbing layer, repelling frequently occurs, and after the coating, blocking among the supports takes place. Thus, it has been quite difficult to choose those subbing agents and antistatic agents which are free from the problems described above.
Recently, a procedure has been proposed in which a photographic emulsion layer is provided on a support only after surface treatment (for example, corona discharge treatment, flame treatment, ultraviolet ray treatment, high frequency wave treatment, glow discharge treatment, plasma treatment, ozone oxidation treatment, etc.) of the support without providing any subbing layer, in order to reduce the complexity of the subbing step and to decrease the production costs. However, the surface resistivity of the support subjected to the surface treatment is always more than 10.sup.14 .OMEGA.. Therefore, a coating step performed to lower the surface resistivity has been required, and it has not been possible to practically employ the no-subbing technology which has been devised for reducing production costs.
The antistatic treatment of the support surface, which is essential for preventing the formation of static marks during the production of the light-sensitive material, generally has little influence on the antistatic properties of the product light-sensitive material. That is to say, to render the light-sensitive material free from the formation of static marks upon subsequent handling, it is necessary to use an additional antistatic treatment on the outermost photographic layers. In this sense, the antistatic treatment of the support surface is quite uneconomical since it is useful only in production steps. Therefore, there has been desired a procedure which enables one to prevent the formation of static marks during the production of a light-sensitive material without applying any such antistatic treatment.